Thermal relay



B. H ssmm-a May 11 1926.

THERMAL RELAY 2 Shams-Sheet 3 Filed Feb.

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mvENToR m H. SmiI/z 1/ Bly'am ATTORNEY 5. H. SMITH May 11 1926.

THERMAL RELAY Filed Feb. 26. 1921 I 2 Sheets-Shet 2 .INVENTOR Bery'a hh.Sm/#7.

A'I'TORNEY WITNESSES:

Patel-flied May 11, 1926. I I 1 UNITED STATES PATENT OFFICE.

BENJAMIN E. SMITH, OF WILK INSBURG, PENNSYLVANIA, ASSIGHOR T WESTDTG-HOUSE ELECTRIC 8t MANUFACTURING COMPANY, A COBPQEJATIQN OF PENN"-SYLVANIA.

THERMAL RELAY.

Application filed February 26, 1921. Serial No. 4118,1 34.

My invention relates to relays and partion therewith of the indicatorsof the con- 65 ticularly to thermal relays. tact nembers I One object ofmy invention is to provide Fig. 7 is a side elevational view of the diala thermal relay that shall have a long time and the indicatorsillustrated in Fi 6; and:

element in its operation. Fig. 8 is a diagrammatic view 0 an elec-Another object of my invention 18 to protrical circuit, illustrating theconnections 00 vide a relay. of the above indicated characthereto of therelay embodying my inventor. for protecting electrical apparatus andtron.

that shall reproduce substantially the temlieterrihg to-Figs. 1 and 2,the device em- 10 pew/cure onditigns bt ining in the appaundying myinvention, c.ompr1ses,1n general,

rams a supporting base 10, a relay 11 supported 6 A further object of myinvention is tot thereon and a cover 12 that co-operates with provide arelay of the above indicated chap thebaseltl to enclose the relay 11.The base actor that shall be simple and economical in 10 is providedWith two supporting brackets '15 its construction and reliable in itsoperation. 13 and 14, each of which is provided with a In practicing myinvention, I provide two threaded rod -l5 that extends outward from "Jspirally-wound bimetallic members that are the r Ilt 0f the relay andco-operates with mounted on a movable shaft. The inner & thumb crew 16to hold the cover 12 in ends of the bimetallic members areelectriposition. Threaded portions 17 that extend 20 cally connectedthrough a sleeve of confrom the rear of the base 10 co-operate withducting material that is securely mounted on a i h board 01' somesimilar supporting 7 the shaft and insulated therefrom. The ev ce toSupport the relay in any desired outer ends of the bimetallic membersare P EI H. secured to stationary terminals that are dish relay llcomprlses a fluid-containing posed on an enclosing i Th bi t lreceptacle20 that is mounted'on, and suplie members are traversed by the circuitcur- P r d by, a Supporting member 21 which is rent, and, when heated,turn the shaft upon secured to thebase .10. Supported within which theyare mounted to effect engagement he receptacle, between two bearings 22and between two contact members. The bimetal- IS a Shaf 24 upon which isdisposed a lie membersare immersed in oil or some tube 95 9f insulatingmaterial. Upon the similar fluid having a large heat capacity. tube 251s ly n d a le v 26 of so The combination of the fluid and the bime-Conducting material.

tallio member so increases the thermal- TW spirally-wound bimetallicmemb rs storage capacity of the relay as to reproduce 27 n 28 are supprted by the conducting substantially the temperature conditions inSleeve 2 n h ve their inner ends'secured th l t i l apparatus th t i t bthereto, being thus electrically connected to no tected. each other. Theouter ends of the members gum 1 of h accompanying d i i 27 and 28 arerespectively connected to two a front view. partially in elevation andpartglmlnal m r 29 and 30. The terminal w in tialiy in section, of athermal relay embod members 29 and 30 are connected by flexible m my iti I conductors to terminal members 31 and 32, 95

Fig. 2 is a side view, partially in elevation where y the bimetallicmembers 27 and 28 and partially in section, with parts broken of therelay may be connected in circuit with away, of the relay shown inFig. 1. the external conductors of the main circuit Fig. 3 is a planview of: the relay taken which is to be protected.

along the line III1II of Fig. land illus-' A spirally-wound spring 33 isdisposed 2.00 trates the contact-adjusting member. around the insulatingtube 25 and has the Fig. 4 is a plan view of the adjustable inner endthereof secured to the tube and the. contact-supporting member of therelay outer end secured to the fluid-containing reshown in Fig. l.ceptacle 20. Also men lnpon the shaft of F 5 is a plan view of themovable the insuiat-in a contact member 10 contact-supporting member.34, the moi 01 cinch. with the shai'it Fig. 6 is a front elevationalview of the 24, is GOIltIOll i by the expansion or contrac scale of therelay, illustrating the co-operation of the The spring? 33 serves as aconducting means to connect,

the contact member 34 to an external control circuit, as illustrated inthe diagram of Fi 8.

Th the path of the movable contact mem ber 34 is an adjustable contactmember 35 that is adapted to be engaged thereby. The contact member 35is secured between one pole of a circular permanent magnet 36 and asupporting disc 37 of micarta, as illustrated in Fig. 4. The disc 37 ofmicarta is disposed on, and supported by, the spindle 38 of the memberserving as the bearing 22.

The contact members 34 and 35 are disposed on supporting members 39 and40 of magnetizable material, and the engagement of the contact membersis, therefore, effectively maintained. The disengagement of the contactmembers is effected with a snap action by reason of the force of thetensioned bimetallic members 27 and 28 acting upon the contact member 34to disengage the same from the contact member 35. The po-v sition of thecontact member 35 is controlled by the adjusting member 44 whichisretained in such position as it may be placed and. prevented from movingtherefrom,. because of jarring or vibration, by means of a flexed spring45.

Thecontact members 34 and 35 are connected to two terminal members 46and 47, respectively, to permit convenient connection thereto of theconductors of an external control circuit.

The supporting members 39 and 40 of the contact members are providedwith pointers 41 and 42, respectively, that co-operate with a stationaryscale. 43 to indicate, respective ly, the position of the'movable and ofthe stationary contact members, as illustrated in Fig. 6. The scale maybe calibrated for average value of current or temperature or forpercentage of full-load circuit.

The fluid container is provided with a window or opening 48 throughwhich the position of the contact members 34 and 35 may be observed.

, Thebimetallic members are immersed in oil or some similar fluid havinga large heatstorage capacity and they thus serve to simulate the heatingconditions of an electrical apparatus which is to be protected by therelay. The temperature of the bimetallic members will thus varysubstantially in accordance with the temperature of the conductors ofthe apparatus that is to be protected and such control as may be desired.may be obtained by means of a control circuit, the energization ofwhich is controlled y engagement of the contact members.

As illustrated in the diagram shown in Fig. 8, a translating device 50is adapted to receive energy from the source 51 of elec tromotive forcethrough the circuit interrupter 52. The circuit current that traversesmember controlled by the shaft and an oilthe translating device 50 alsotraverses the bimetallic elements 27 and 28 and, be cause of thesurrounding oil, heats those members substantially in accordance withthe heating of the translating device 50. When the temperature of thetranslatingdcvice 50 and, accordingly, the temperature of the relayattains a. predetermined value, engagement of the contact members iseffected to complete a control circuit for tripping the 7 interrupter.

It will thus be observed that, by immersing in oil or some other suchheat-storage fluid, a bimetallic member that is traversed by the samecurrent that traverses the translating device, a thermal relay may beobtained which will closely simulate the temperature conditionsobtaining in the translating device.

My invention is not limited to the specific 85 arrangements or'detailsas illustrated, since various modifications may be made therein withoutdeparting from the spirit and scope of the invention, as set forth ,inthe appended claims.

'I claim as my invention 1. A thermal relay comprising a movable shaft,a sleeve of conducting material disposed thereon and insulatedtherefrom, a plurality of spirally-wound bimetallic members disposed onthe conducting sleeve, 2. contact member controlled by the movement ofthe shaft caused by the metallic members and an oil-containing vesselfor enclosing the bimetallic member.

2. A thermal relay having a long time element in its operation forprotecting an electrical apparatus comprising a plurality ofspirally-wound bimetallic members incircuit with the apparatus, amovable shaft, 1 a sleeve of conducting material securely disposed onthe shaft but insulated therefrom and having the inner ends of thebimetallic members secured to the sleeve, a contact containing vesselfor enclosing the bimetallie members and serving to increase the thermalcapacity thereof to cause the same to have a heating characteristicsubstantially in accordance with the heating characteristic of theapparatus to be protected. 3. A thermal relay for protecting anelectrical apparatus comprising a bimetallic member traversed by thecircuit current and immersed in oil to provide an increased heat-storagecapacity to cause that member to have a heating characteristicsubstantially in accordance with the heating characteristic contactmember controlled by the shaft, an

adjustable contact member adapted to be .engaged by the formercontactmember, means cooperating with the bearing for adjusting saidmember, and means for causing the engagement and the disengagement of hecontact members to be effected with a snap action.

5. A thermal relay comprising an opaque vessel adapted to contain afluid having heatstorage qualities,- said vessel being provided with anopening serving as a Window, transparent means disposed behind saidopening and arranged to co-operate' with the vessel to preclude thefluid from issuing through the window, a thermally-responsive memberdisposed in the fluid, a contact member controlled thereby, and anindicating scale disposed behind the window to indicate the position ofthe contact member.

6. A thermal relay comprising a fluid container,bearings disposed in thetop and the bottom portions, a shaftdisposed between the bearings, athermal element for controlling the shaft, 9. contact member to becontrolled by the shaft and means whereby the position of the contactmember may be adjusted by the upper bearing from the outside of thecontainer.

7. A thermal relay comprising a fluid dontainer, bearings disposed inthe top and the bottom portions, a contact member, means disposedbetween the bearings and operative to control the contact member andmeans disposed externally relative to the container and co-operatingwith one bearing for adjusting the contact member.

Y 8. The combination with a closed casing containing an operatingelement, of a bearing therefor extending through the casing, a contactmember disposed in the casing and controlled by the operating'elementand means externally disposed relative to the container and cooperatingwith the bearing to control the adjustment of the contact member.

In testimony whereof, I have hereunto .subscribed my name, this 15th dayof February 1921. g

. BENJAMIN H. SMITH.

